PubMed Health⌕ Search

Biomedical subjects

Arthur M Friedlander

Publications and source records attributed to Arthur M Friedlander.

16 recordsLinked to original sources
PubMed2006

Poly-gamma-glutamate capsule-degrading enzyme treatment enhances phagocytosis and killing of encapsulated Bacillus anthracis.

The poly-gamma-d-glutamic acid capsule confers antiphagocytic properties on Bacillus anthracis and is essential for virulence. In this study, we showed that CapD, a gamma-polyglutamic acid depolymerase encoded on the B. anthracis capsule plasmid, degraded purified capsule and removed the capsule from the surface of anthrax bacilli. Treatment with CapD induced macrophage phagocytosis of encapsulated B. anthracis and enabled human neutrophils to kill encapsulated organisms. A second glutamylase, PghP, a gamma-polyglutamic acid hydrolase encoded by Bacillus subtilis bacteriophage PhiNIT1, had minimal activity in degrading B. anthracis capsule, no effect on macrophage phagocytosis, and only minimal enhancement of neutrophil killing. Thus, the levels of both phagocytosis and killing corresponded to the degree of enzyme-mediated capsule degradation. The use of enzymes to degrade the capsule and enable phagocytic killing of B. anthracis offers a new approach to the therapy of anthrax.

Animals↗
PubMed2006

Short-course postexposure antibiotic prophylaxis combined with vaccination protects against experimental inhalational anthrax.

Prevention of inhalational anthrax after Bacillus anthracis spore exposure requires a prolonged course of antibiotic prophylaxis. In response to the 2001 anthrax attack in the United States, approximately 10,000 people were offered 60 days of antibiotic prophylaxis to prevent inhalational anthrax, but adherence to this regimen was poor. We sought to determine whether a short course of antibiotic prophylaxis after exposure could protect non-human primates from a high-dose spore challenge if vaccination was combined with antibiotics. Two groups of 10 rhesus macaques were exposed to approximately 1,600 LD50 of spores by aerosol. Both groups were given ciprofloxacin by orogastric tube twice daily for 14 days, beginning 1-2 h after exposure. One group also received three doses of the licensed human anthrax vaccine (anthrax vaccine adsorbed) after exposure. In the ciprofloxacin-only group, four of nine monkeys (44%) survived the challenge. In contrast, all 10 monkeys that received 14 days of antibiotic plus anthrax vaccine adsorbed survived (P = 0.011). Thus postexposure vaccination enhanced the protection afforded by 14 days of antibiotic prophylaxis alone and completely protected animals against inhalational anthrax. These data provide evidence that postexposure vaccination can shorten the duration of antibiotic prophylaxis required to protect against inhalational anthrax and may impact public health management of a bioterrorism event.

Administration, Inhalation↗
PubMed2006

Anthrax lethal toxin impairs innate immune functions of alveolar macrophages and facilitates Bacillus anthracis survival.

Alveolar macrophages (AM) are very important for pulmonary innate immune responses against invading inhaled pathogens because they directly kill the organisms and initiate a cascade of innate and adaptive immune responses. Although several factors contribute to inhalational anthrax, we hypothesized that unimpeded infection of Bacillus anthracis is directly linked to disabling the innate immune functions contributed by AM. Here, we investigated the effects of lethal toxin (LT), one of the binary complex virulence factors produced by B. anthracis, on freshly isolated nonhuman primate AM. Exposure of AM to doses of LT that killed susceptible macrophages had no effect on the viability of AM, despite complete MEK1 cleavage. Intoxicated AM remained fully capable of B. anthracis spore phagocytosis. However, pretreatment of AM with LT resulted in a significant decrease in the clearance of both the Sterne strain and the fully virulent Ames strain of B. anthracis, which may have been a result of impaired AM secretion of proinflammatory cytokines. Our data imply that cytolysis does not correlate with MEK1 cleavage, and this is the first report of LT-mediated impairment of nonhuman primate AM bactericidal activity against B. anthracis.

Animals↗
PubMed2005

The discovery of a potent and selective lethal factor inhibitor for adjunct therapy of anthrax infection.

A potent and selective anthrax LF inhibitor 40, (2R)-2-[(4-fluoro-3-methylphenyl)sulfonylamino]-N-hydroxy-2-(tetrahydro-2H-pyran-4-yl)acetamide, was identified through SAR study of a high throughput screen lead. It has an IC50 of 54 nM in the enzyme assay and an IC50 of 210 nM in the macrophage cytotoxicity assay. Compound 40 is also effective in vivo in several animal model studies.

Animals↗
PubMed2005

Construction of a rhamnose mutation in Bacillus anthracis affects adherence to macrophages but not virulence in guinea pigs.

Carbohydrate analyses of whole-spore extracts have confirmed the presence of rhamnose in the spore of the fully virulent Ames strain of Bacillus anthracis. A gene cluster containing loci with high homology to the rhamnose biosynthetic genes, rmlACBD, was identified within the B. anthracis chromosome. The first gene of this cluster, rmlA, was inactivated by forming a merodiploid cointegrate using an internal fragment of the gene within the Ames strain of B. anthracis to construct the mutant strain Ames-JAB1. Carbohydrate analysis of spores from this mutant demonstrated the loss of rhamnose. When assaying for spore infection of macrophages, we detected a significant decrease in the recovery with the Ames-JAB1 strain compared to the recovery with the Ames wild-type strain. When pre-treating macrophages with cytochalasin-D, spores of the mutant were further hindered in recovery, indicating that the spores were not able to bind as well to the macrophages. However, in guinea pigs challenge experiments, no difference in virulence was observed between the mutant and wild-type strains. These results suggest that the incorporation of rhamnose into the spore coat of B. anthracis is required for optimal interaction with macrophages but is not required for full virulence in this animal model.

Animals↗
PubMed2004

Anthrax capsule vaccine protects against experimental infection.

Efficacy of a poly-gamma-D-glutamic acid anthrax capsule vaccine was assessed in a mouse model of infection. Capsule by itself was protective against lethal challenge with a toxin(-), capsule(+) Bacillus anthracis strain. Conjugation of capsule to bovine serum albumin resulted in enhanced IgG anti-capsule antibodies measured by ELISA, but completely abrogated the protection. The protective unconjugated capsule vaccine elicited significantly higher IgM titers and opsonic activity than did the non-protective capsule conjugate. When tested against a fully virulent toxin(+), capsule(+) B. anthracis strain, neither capsule nor protective antigen alone was protective. However, the combination of the two protected against a lethal challenge. These results suggest that capsule may enhance the protection afforded by protective antigen vaccines against anthrax if opsonizing antibodies are produced. Surprisingly, some protection was also observed when protective antigen was conjugated to itself.

Animals↗
PubMed2004

The NheA component of the non-hemolytic enterotoxin of Bacillus cereus is produced by Bacillus anthracis but is not required for virulence.

A non-hemolytic enterotoxin (NHE) is one of the two enterotoxins thought to cause diarrhea produced by Bacillus cereus. We identified genes in Bacillus anthracis homologous to the B. cereus nheAB genes encoding proteins of the NHE complex. The NheA component was detected immunologically in culture supernatants from B. anthracis but not from a NheA(-) mutant, suggesting that B. anthracis produces and secretes the NheA subunit of NHE. A NheA deletion mutant was not attenuated in the guinea pig suggesting that NheA is not absolutely required for virulence.

Amino Acid Sequence↗
PubMed2004

Needle-free skin patch vaccination method for anthrax.

Three immunizations of mice with recombinant protective antigen (rPA) by transcutaneous immunization (TCI) induced long-term neutralizing antibody titers that were superior to those obtained with aluminum-adsorbed rPA. In addition, rPA alone exhibited adjuvant activity for TCI. Forty-six weeks after completion of TCI, 100% protection was observed against lethal anthrax challenge.

Adjuvants, Immunologic↗
PubMed2004

Enhancement of anthrax lethal toxin cytotoxicity: a subset of monoclonal antibodies against protective antigen increases lethal toxin-mediated killing of murine macrophages.

We investigated the ability of using monoclonal antibodies (MAbs) against anthrax protective antigen (PA), an anthrax exotoxin component, to modulate exotoxin cytotoxic activity on target macrophage cell lines. Anthrax PA plays a critical role in the pathogenesis of Bacillus anthracis infection. PA is the cell-binding component of the two anthrax exotoxins: lethal toxin (LeTx) and edema toxin. Several MAbs that bind the PA component of LeTx are known to neutralize LeTx-mediated killing of target macrophages. Here we describe for the first time an overlooked population of anti-PA MAbs that, in contrast, function to increase the potency of LeTx against murine macrophage cell lines. The results support a possible mechanism of enhancement: binding of MAb to PA on the macrophage cell surface stabilizes the PA by interaction of MAb with macrophage Fcgamma receptors. This results in an increase in the amount of PA bound to the cell surface, which in turn leads to an enhancement in cell killing, most likely due to increased internalization of LF. Blocking of PA-receptor binding eliminates enhancement by MAb, demonstrating the importance of this step for the observed enhancement. The additional significance of these results is that, at least in mice, immunization with PA appears to elicit a poly-clonal response that has a significant prevalence of MAbs that enhance LeTx-mediated killing in macrophages.

Animals↗
PubMed2004

Recombinant F1-V fusion protein protects black-footed ferrets (Mustela nigripes) against virulent Yersinia pestis infection.

Black-footed ferrets (Mustela nigripes) are highly susceptible to sylvatic plague, caused by the bacterium Yersinia pestis, and this disease has severely hampered efforts to restore ferrets to their historic range. A study was conducted to assess the efficacy of vaccination of black-footed ferrets against plague using a recombinant protein vaccine, designated F1-V, developed by personnel at the U.S. Army Medical Research Institute of Infectious Diseases. Seven postreproductive black-footed ferrets were immunized with the vaccine, followed by two booster immunizations on days 23 and 154; three control black-footed ferrets received a placebo. After the second immunization, antibody titers to both F1 and V antigen were found to be significantly higher in vaccinates than controls. On challenge with 7,800 colony-forming units of virulent plague by s.c. injection, the three control animals died within 3 days, but six of seven vaccinates survived with no ill effects. The seventh vaccinate died on day 8. These results indicate that black-footed ferrets can be immunized against plague induced by the s.c. route, similar to fleabite injection.

Animals↗
PubMed2003

The genome sequence of Bacillus anthracis Ames and comparison to closely related bacteria.

Bacillus anthracis is an endospore-forming bacterium that causes inhalational anthrax. Key virulence genes are found on plasmids (extra-chromosomal, circular, double-stranded DNA molecules) pXO1 (ref. 2) and pXO2 (ref. 3). To identify additional genes that might contribute to virulence, we analysed the complete sequence of the chromosome of B. anthracis Ames (about 5.23 megabases). We found several chromosomally encoded proteins that may contribute to pathogenicity--including haemolysins, phospholipases and iron acquisition functions--and identified numerous surface proteins that might be important targets for vaccines and drugs. Almost all these putative chromosomal virulence and surface proteins have homologues in Bacillus cereus, highlighting the similarity of B. anthracis to near-neighbours that are not associated with anthrax. By performing a comparative genome hybridization of 19 B. cereus and Bacillus thuringiensis strains against a B. anthracis DNA microarray, we confirmed the general similarity of chromosomal genes among this group of close relatives. However, we found that the gene sequences of pXO1 and pXO2 were more variable between strains, suggesting plasmid mobility in the group. The complete sequence of B. anthracis is a step towards a better understanding of anthrax pathogenesis.

Bacillus anthracis↗
PubMed2002

Antibody response to a delayed booster dose of anthrax vaccine and botulinum toxoid.

We evaluated the prevalence and concentration of serum antibodies 18-24 months after primary inoculation with anthrax and botulinum vaccines, and assessed the reactogenicity and immunogenicity of a significantly delayed booster dose of these vaccines. Five hundred and eight male active-duty military personnel received one, two or three inoculations with anthrax vaccine and/or botulinum toxoid in 1990/1991 in preparation for Operations Desert Shield/Desert Storm. Subjects were vaccinated with the licensed anthrax vaccine, adsorbed (AVA) and pentavalent (ABCDE) botulinum toxoid (PBT) BB-IND 3723. Anthrax protective antigen (PA) IgG antibody was measured in serum using an immunocapture enzyme-linked immunosorbent assay (ELISA). A mouse neutralization test was used to determine the titer of Clostridium botulinum type A antitoxin in serum samples. The prevalence of anti-PA IgG was 30% in individuals 18-24 months after priming with one, two or three doses of AVA. After boosting, 99% of volunteers had detectable anti-PA IgG; only two individuals failed to respond. The prevalence of antibodies against botulinum toxin type A was 28% 18-24 months after initial priming. Following boosting, 99% of volunteers had serum titers >0.02IU/ml, and 97% responded with titers > or =0.25IU/ml. Systemic reactions to booster vaccinations could not be specifically ascribed to one or the other vaccine, but were generally mild and of brief duration. Forty-five percent of volunteers reported one or more systemic reactions over the course of 7 days. Injection site reactions of any kind occurred in 25% of AVA recipients and in 16% of PBT recipients; persistence of local reactions beyond 7 days was infrequent. While the kinetics and durability of immune responses must be studied, these findings suggest that booster doses of anthrax vaccine and botulinum toxoid sufficient to stimulate a robust anamnestic response may be given at times distant from receipt of the primary inoculations.

Adult↗
PubMed2002

Anthrax as a biological weapon, 2002: updated recommendations for management.

OBJECTIVE: To review and update consensus-based recommendations for medical and public health professionals following a Bacillus anthracis attack against a civilian population. PARTICIPANTS: The working group included 23 experts from academic medical centers, research organizations, and governmental, military, public health, and emergency management institutions and agencies. EVIDENCE: MEDLINE databases were searched from January 1966 to January 2002, using the Medical Subject Headings anthrax, Bacillus anthracis, biological weapon, biological terrorism, biological warfare, and biowarfare. Reference review identified work published before 1966. Participants identified unpublished sources. CONSENSUS PROCESS: The first draft synthesized the gathered information. Written comments were incorporated into subsequent drafts. The final statement incorporated all relevant evidence from the search along with consensus recommendations. CONCLUSIONS: Specific recommendations include diagnosis of anthrax infection, indications for vaccination, therapy, postexposure prophylaxis, decontamination of the environment, and suggested research. This revised consensus statement presents new information based on the analysis of the anthrax attacks of 2001, including developments in the investigation of the anthrax attacks of 2001; important symptoms, signs, and laboratory studies; new diagnostic clues that may help future recognition of this disease; current anthrax vaccine information; updated antibiotic therapeutic considerations; and judgments about environmental surveillance and decontamination.

Adolescent↗
PubMed2002

Anthrax vaccine: immunogenicity and safety of a dose-reduction, route-change comparison study in humans.

Anthrax vaccine adsorbed (AVA), an effective countermeasure against anthrax, is administered as six subcutaneous (SQ) doses over 18 months. To optimize the vaccination schedule and route of administration, we performed a prospective pilot study comparing the use of fewer AVA doses administered intramuscularly (IM) or SQ with the current schedule and route. We enrolled 173 volunteers, randomized to seven groups, who were given AVA once IM or SQ; two doses, 2 or 4 weeks apart, IM or SQ; or six doses at 0, 2, 4 weeks and 6, 12, and 18 months (control group, licensed schedule and route). IM administration of AVA was associated with fewer injection site reactions than SQ administration. Following the first SQ dose of AVA, compared to males, females had a significantly higher rate of injection site reactions such as erythema, induration and subcutaneous nodules (P<0.001). Reaction rates decreased with a longer dose interval between the first two doses. The peak anti-PA IgG antibody response of subjects given two doses of AVA 4 weeks apart IM or SQ was comparable to that seen among subjects who received three doses of AVA at 2-week intervals. The IM route of administering this aluminum hydroxide adsorbed vaccine is safe and has comparable peak anti-PA IgG antibody levels when two doses are administered 4 weeks apart compared to the licensed initial dose schedule of three doses administered 2 weeks apart. A large pivotal study is being planned by the Centers for Disease Control and Prevention to confirm these results.

Adult↗
PubMed1996

Characterization of lethal factor binding and cell receptor binding domains of protective antigen of Bacillus anthracis using monoclonal antibodies.

Lethal toxin from Bacillus anthracis is composed of protective antigen (PA) and lethal factor (LF). Anti-PA mAbs that neutralized lethal toxin activity, either in vivo or in vitro, identified three non-overlapping antigenic regions on PA. Two distinct antigenic regions were recognized by the four mAbs that neutralized lethal toxin activity by inhibiting the binding of 125I-LF to cell-bound PA. Mapping showed that one mAb, 1G3PA63, recognized an epitope on a 17 kDa fragment located between amino acid residues Ser-168 and Phe-314. The three other mAbs, 2D3PA, 2D5PA and 10D2PA, recognized an epitope between amino acids Ile-581 and Asn-601. A single antigenic region was recognized by the three mAbs, 3B6PA, 14B7PA and 10E10PA63, that inhibited binding of 125I-PA to cells. This region was located between amino acids Asp-671 and Ile-721. These results confirm previously defined functional domains of PA and suggest that LF may interact with two different sites on PA to form lethal toxin.

Antibodies, Monoclonal↗